Age-related macular degeneration (AMD) and glaucoma are two of the leading causes of blindness in the United States and across the world. Present glaucoma therapies generally require polypharmacy, where subjects are often prescribed several topical agents that must be applied to the eye with varying frequencies, in some cases up to 3 or 4 times a day. These dosing regimens are often difficult for subjects to consistently follow, and many individuals progress to needing surgical treatments such as intraocular shunts or trabeculectomies, which have significant attendant complications.
Subjects having macular degeneration are often required to have monthly intravitreal injections. Such injections are painful and may lead to retinal detachment, endophthalmitis, and other complications. Furthermore, these injections are generally performed only by retinal surgeons, a small fraction of the ophthalmic community, producing a bottleneck in eye care delivery and increased expense.
Postoperative surgery inflammation is associated with raise intraocular pressure (TOP), and increase the likelihood of cystoid macular edema (CME), synechial formation, posterior capsule opacification (PCO), and secondary glaucoma. Patient compliance is of concern in the management of postoperative inflammation because multiple eye drops must be taken multiple times per day at regular intervals over the course of weeks. Poor compliance compromises the efficacy of topical drugs, which are further limited by corneal absorption and have highly variable intraocular concentrations during the therapeutic course. Uveitis specifically refers to inflammation of the middle layer of the eye, termed the “uvea” but in common usage may refer to any inflammatory process involving the interior of the eye. Uveitis is estimated to be responsible for approximately 10% of the blindness in the United States.
Postoperative cataract surgery inflammation can be well controlled by improving patient compliance. Available literature and experience shows penetration of the drug after topical administration is poor and higher systemic concentration means frequent systemic adverse events. All of these factors highlight the need for sustained intraocular delivery for pharmaceutical active agents to effectively control inflammation.